Urea derivatives and their use as herbicides

ABSTRACT

Method of controlling weeds in cotton with fluoroalkoxy ureas.

This is a divisional application of application Ser. No. 40,704 filedMay 26, 1970, now U.S. Pat. No. 3,937,726 granted Feb. 10, 1976, whichin turn is a continuation-in-part application of applications Ser. No.628,843 filed Apr. 6, 1967, Ser. No. 799,088 filed Feb. 13, 1969, andSer. No. 800,748 filed Feb. 19, 1969, all now abandoned.

The present invention relates to novel derivatives of the generalformula ##STR1## in which R₁ stands for a haloalkyl, halocycloalkyl,haloalkenyl or halocycloalkenyl radical each having 2 to 5 carbon atoms,the halogen being fluorine, chlorine and/or bromine, n₁ is 1 or 2, R₄stands for a halogen atom, the trifluoromethyl-radical or for an alkyl-or alkoxy-radical with 1 to 3 carbon atoms, n₂ is 0, 1, 2 or 3, R₂stands for a hydrogen atom or an alkyl radical with 1 to 4 carbon atomsand R₃ stands for an alkyl- or alkoxy-radical each having 1 to 4 carbonatoms.

The specified compounds are obtained by reacting

1. halogenoalkoxy-arylisocyanates or halogenoalkoxy-aryl-carbamic acidchlorides with

A. alkyl- or dialkyl-amines or O-alkyl- or O,N-dialkylhydroxylamines or

B. O-alkylhydroxyl-amines with subsequent alkylation or

C. N-alkylhydroxyl-amines with subsequent alkylation or

D. hydroxyl-amine with subsequent dialkylation; or reacting

2. halogenoalkoxy-arylamines with alkylisocyanates or di-alkylcarbamicacid chlorides.

The compounds can be prepared, for example, in one of the followingways: ##STR2##

The reactions of the halogenoalkoxy-arylisocyanates or carbamic acidchlorides with the amines or alkylated hydroxylamines are preferablycarried out at a temperature below 80° C in the presence or absence of adiluent. Suitable diluents are, for example, benzene, toluene, dioxaneor dimethyl formamide.

The corresponding reactions with hydroxylamine are advantageouslyperformed at a temperature below 40° C, in a two-phase mixture of waterand an organic solvent immiscible with water.

The alkylations are suitably carried out in aqueous-alkaline suspensionor in mixtures of aqueous alkali and an organic solvent. The alkalimetal hydroxide solution and the alkylating agent are advantageouslyadded simultaneously. Alternatively, the urea may be placed first in thereaction vessel together with the alkylating agent in an organic solventand the alkali metal hydroxide solution may then be added or, in thecase of compounds that are less sensitive towards alkali, the order ofaddition may be reversed. The reaction temperature naturally depends onthe reactivity of the alkylating agents used and is in the range from10° to 90° C.

The alkylations in processes (1b), (1c), and (1d) are carried out withdialkyl-sulfates, alkyl halides or alkyl-toluene-sulfonates. In (2)anilines carrying corresponding substituents are used.

Suitable starting compounds for processes (1a), (1b), (1c), and (1d)are, for example, 3- or4-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenylisocyanate,3-methyl-4-(1',1',2'-tri-fluoro-2'-chloro-ethoxy)-phenylisocyanate, 3-or 4-(1',1',2',2',-tetra-fluoro-ethoxy)-phenylisocyanate,3-methyl-4-(1',1',2',2'-tetrafluoro-ethoxy)-phenylisocyanate, 3- or4-(1',1',2',3',3',3'-hexafluoro-propoxy)-phenylisocyanate,3-methyl-4-(1',1',2',3', 3',3'-hexafluoro-propoxy)-phenylisocyanate,3-(1',1',2'-tri-fluoro-ethoxy)-phenylisocyanate, 3- or4-(1',1',2'-trifluoro-2'-bromo-ethoxy)-phenylisocyanate,3-methyl-4-(1',1',2'-tri-fluoro-2'-bromo-ethoxy)-phenylisocyanate, 3- or4-(1',1'-di-fluoro-2',2'-dichloro-ethoxy)-phenylisocyanate,4-(3',3'-di-chloroallyloxy)-phenylisocyanate,4-(2',3',3'-trichloroallyloxy)-phenylisocyanate,4-(1',2'-dichlorovinyloxy)-phenylisocyanate,3-chloro-4-(2'-chloroethoxy)-phenylisocyanate,3-methyl-4-(2'-chloroethoxy)-phenylisocyanate and3-trifluoromethyl-4-(2'-chloro-ethoxy)-phenylisocyanate and otheranalogous phenylisocyanates having in the R₄ -position for examplechloro- or bromo-, or the methyl-, methoxy-, ethyl- or propyl -radical.

Instead of the isocyanates phenylcarbamic acid chlorides carrying thecorresponding substituents may also be used.

The novel isocyanates are obtained by phosgenation of the correspondingamines or the hydrochlorides which can be prepared by the followingmethods A, B, C and D. Method A consists in the reaction of alkali metalnitro-phenolates with halogenated alkenes (trichloroethylene,tribromoethylene, trichloropropene, tetrachloropropene), halogenatedcycloalkenes (hexafluoro-dichloro-cyclopentene,tetrafluoro-dichloro-cyclobutene) and halogenated alkanes(1,1-di-fluoro-1,2,2-tri-ethane chloride etc.) analogous to (1) Britishpatent specification 617 820; C.A. 43 (1949) 7045 et seq., (2) Ber. 96(1963) 52, (3) Ind. Chem. 39 (1947) 412; and the subsequent catalyticreduction of the nitro-compound thus obtained.

The following examples serve to illustrate the reaction conditions.

EXAMPLE: Preparation of the 3-(1',2'-dichlorovinyloxy)-aniline

161 grams (1 mole) of 3-nitrophenol sodium were dissolved in 400milliliters of dimethyl formamide and 145 grams (1.1 mole) oftrichloroethylene were dropped in at 60° C. Subsequently the mixture wasstirred for 6 hours at 80° C. The main amount of dimethyl formamide wasdistilled off in vacuo. The oily residue was poured into ice water, wasseparated, dried over Na₂ SO₄ and distilled.

Kp_(o)._(o1) mm: 115° - 117° C; Yield: 115 grams of3-(1',2'-dichlorovinyloxy)-nitrobenzene

1 mole of the nitro-product was dissolved in 1 liter of ethanol and wasreduced by means of hydrogen in an autoclave at 60° C, after 5 grams ofa Raney-nickel catalyst (R/50) had been added. The catalyst was thenfiltered off with suction, the ethanol was distilled off, and theresidue was distilled in vacuo.

Kp_(o).₅ mm: 116° - 118° C Yield: 121 grams of3-(1',2'-dichlorovinyloxy)-aniline. Method B consists in the reaction ofnitro- or acetamino-phenols with halogenated alkanes(1,1-difluoro-1,2,2-trichloro-ethane, 1,1,2-trifluoro-1,2-dibromoethane)and halogenated alkenes (trichloroethylene etc.) in the presence of K₂CO₃ analogous to (4) J. Am. Chem. Soc. 70 (1948) 593; and in theconversion of the nitro-compound into aniline, as described by Method A,or the cleavage of the acetamino compound into the anilinehydrochloride.

The following example serves to illustrate the process:

EXAMPLE: Preparation of the 3-acetamino-(1',1'-difluoro-2',2'-dichloro)-phenetol.

151 grams (1 mole) of 3-acetamino-phenol were dissolved in 400milliliters of dimethyl formamide, and 138 grams (1 mole) of K₂ CO₃ wereadded, while stirring, 186 grams (1.1 mole) of1,1-difluoro-1,2,2-trichloro-ethane were dropped into the mixture at 60°C; the mixture was maintained at 80° C for 6 hours and was then pouredinto about 4 liters of ice water. The precipitated crystalline productwas filtered off with suction and dried.

Melting point: 72° - 74° C Yield: 281 grams of3-acetamino-(1',1'-difluoro-2',2'-dichloro)-phenetol

1 mole of acetamino compound was dissolved in 2 liters of hydrochloricacid of 18% strength, while heating, and was maintained at 100° C for 2hours. After cooling, the precipitated crystalline product was filteredoff with suction and dried.

Melting point: 227° C; Yield: 230 grams of3-(1',1'-difluoro-2',2'-dichloroethoxy)aniline hydrochloride.

Method C consists in the reaction of nitro-phenols or aminophenols, inparticular 3-amino-phenol, with halogenated alkenes(tetrafluoro-ethylene, trifluoro-ethylene, trifluoro-chloroethylene,hexafluoro-propene, difluoro-dichloroethylene etc.) analogous to (5) J.Am. Chem. Soc. 73 (1951) 5831; (6) Bull. Soc. chim. France [5] 1957,581; and the subsequent catalytic reduction, as described by Method A.

EXAMPLE: Preparation of the3-(1',1',2'-trifluoro-2'-chloroethoxy)-aniline.

139 grams (1 mole) of 3-nitro-phenol and 28 grams (0.5 mole) ofpotassium hydroxide were dissolved in 400 milliliters of dimethylformamide, and 140 grams (1.2 mole) of trifluoro-chloroethylene wereintroduced in a gas pipe at 40° C; the mixture was then maintained at60° C for 2 hours. The main amount of dimethyl formamide was distilledoff in vacuo. The residue was poured into ice water, separated, driedover Na₂ SO₄ and distilled in vacuo.

Kp_(o).₃ mm: 89° - 90° C; Yield: 176 grams of3-nitro-(1',1',2'-trifluoro-2'-chloro)-phenetol.

1 mole of the nitro-compound was reduced as described by Method A.

Kp_(o).₁ mm: 86° C Yield: 171 grams of3-(1',1',2'-trifluoro-2'-chloroethoxy)-aniline.

When in the example mentioned above 1 mole of 3-amino-phenol was usedinstead of 3-nitro-phenol, the3-(1',1',2'-trifluoro-2'-chloroethoxy)-aniline was obtained directly.Method D consists in the reaction of nitro-phenolates withβ-chloroethyl-p-toluene sulfonate analogous to (7) J. Chem. Soc. 121(1922) 644, and the subsequent catalytic reduction of the nitro-productsobtained into the anilines, as described by Method A.

EXAMPLE: Preparation of the 4-(2'-chloroethoxy)-aniline

42 grams (1.05 mole) of sodium hydroxide were dissolved in 75milliliters of water, and 139 grams (1 mole) of 4-nitrophenol and 235grams (1 mole) of β-chloroethyl-p-toluene sulfonate were added, whilestirring. Subsequently the reaction mixture was heated at 110° C for 4hours. After cooling, the mixture was made alkaline by means of asolution of sodium hydroxide of 33% strength and was diluted with about5 liters of water. The precipitated crystalline product was filtered offwith suction, washed with water and dried.

Melting point: 54° - 55° C; Yield: 153 grams of4-(2'-chloroethoxy)-nitrobenzene.

1 mole of the nitro-compound was reduced, as described by Method A.

Melting point: 66° C; Yield: 137 grams of 4-(2'-chloroethoxy)-aniline.

All alkoxy-anilines falling under the invention are obtained inaccordance with the Methods A - D mentioned above by using in thepertinent exampler other corresponding substances with the same molenumbers, instead of the reactants mentioned therein. The followingtables give a survey of the preparation and the properties of suchamines.

                                      Table 1                                     __________________________________________________________________________         Nitro- and/or                       Kp/m.p.                              Meth-                                                                              acetamino-                          (mm)                                 od   compound        Reactants           [° C]                         __________________________________________________________________________          ##STR3##                                                                     CCl.sub.2CClH   122 (0.3)                                                A                                                                                   ##STR5##                                                                     CBr.sub.2CBrH   192-196 (3)                                              A                                                                                   ##STR7##                                                                     CCl.sub.2CClH   129-130 (0.4)                                            A                                                                                   ##STR9##                                                                     ClCF.sub.2CCl.sub.2 H                                                                         103- 108 (0.1)                                           C                                                                                   ##STR11##                                                                    CF.sub.2CCl.sub.2                                                                             108 (0.6)                                                A                                                                                   ##STR13##                                                                    ClCF.sub.2CCl.sub.2 H                                                                         37-39                                                    C                                                                                   ##STR15##                                                                    CF.sub.2CCl.sub.2                                                                             133-136 (λ)                                              Aniline           Kp/m.p.                                                                              Analysis                                      Meth-  and/or            (mm)   calcu-                                        od     hydrochloride     [° C]                                                                         lated   found                                 __________________________________________________________________________           120-123 (1)        6.6% N 34.4% Cl                                                                      6.9% N 34.1% Cl                              A                                                                                    139 (0.2)#        4.8% N 54.6% Br                                                                       4.7% N 54.3% Cl                              A                                                                                    125-130 (0.5)      6.5% N 32.9% Cl                                                                      6.7% N 32.7% Cl                              A                                                                                    44-46R20##         5.8% N 29.3% Cl                                                                      6.0% N 29.1% Cl                              C                                                                                    97 (0.3)##         5.8% N 29.3% Cl                                                                      6.0% N 29.1% Cl                              A                                                                                    50-51R22##         5.8% N  29.3% Cl                                                                     5.9% N 29.5% Cl                              C                                                                                    111-114 (0.3)      5.5% N 27.7% Cl                                                                      5.6% N 27.4 Cl                               __________________________________________________________________________

                                      Table II                                    __________________________________________________________________________         Nitro- and/or                                Kp/m.p.                     Meth-                                                                              acetamino-                                   (mm)                        od   compound             Reactants               [° C]                __________________________________________________________________________          ##STR24##                                                                    ClCF.sub.2CCl.sub.2 H                                                                              98                                                  A                                                                                   ##STR26##                                                                    ClCF.sub.2CCl.sub.2 H                                                                              36                                                  A                                                                                   ##STR28##                                                                    ClCF.sub.2CCl.sub.2 H                                                                              95                                                  A                                                                                   ##STR30##                                                                    ClCF.sub.2CCl.sub.2 H                                                                              95                                                  A                                                                                   ##STR32##                                                                    ClCF.sub.2CCl.sub.2 H                                                                              45-47                                               C                                                                                   ##STR34##                                                                    CF.sub.2CFCl         117 (0.6)                                           C                                                                                   ##STR36##                                                                    CF.sub.2CFCl         105-108 (0.6)                                       C                                                                                   ##STR38##                                                                    CF.sub.2CFCl         108-109 (0.3)                                                Aniline               Kp/m.p.        Analysis                        Meth-    and/or                (mm)     calcu-                                od       hydrochloride         [° C]                                                                           lated    found                        __________________________________________________________________________             233STR40##             4.8% N 36.4% Cl                                                                        4.6% N 36.0% Cl                      A                                                                                      135-138 (0.7)          4.9% N 39.7% Cl                                                                        4.7% N 36.3% Cl                      A                                                                                      126-130 (0.5)          5.1% N 38.5% Cl                                                                        5.8% N 38.2% Cl                      A                                                                                      136-140 (0.5)          5.5% N 27.7% Cl                                                                        5.8% N 27.9% Cl                      C                                                                                      92-93 (0.5)            6.2% N 15.7% Cl                                                                        6.4% N 15.5% Cl                      C                                                                                      159-162 (14)           5.4% N 27.3% Cl                                                                        5.6% N 27.5% Cl                      C                                                                                      91-93 (0.2)            5.9% N 14.8% Cl                                                                        5.7% N 14.5% Cl                      __________________________________________________________________________

                                      Table III                                   __________________________________________________________________________         Nitro- and/or                        Kp/m.p.                             Meth-                                                                              acetamino-                           (mm)                                od   compound         Reactants           [° C]                        __________________________________________________________________________          ##STR47##                                                                    CF.sub.2CFH      86 (0.3)                                                C      --                                                                                           CF.sub.2CFH                                             C                                  ##STR50##                                        ##STR51##                                                                    CF.sub.2CF.sub.2 93 (2)                                                  C      --                                                                                           CF.sub.2CF.sub.2                                        C                                  ##STR54##                                        ##STR55##                                                                    CF.sub.2CF.sub.2 42-44                                                   C                                                                                   ##STR57##                                                                    CF.sub.2CF.sub.2 86-88 (0.3)                                             C                                                                                   ##STR59##                                                                    CF.sub.3CFCF.sub.2                                                                             77-79 (0.2)                                                    Aniline             Kp/m.p.                                                                              Analysis                                    Meth-  and/or              (mm)   calcu-                                      od     hydrochloride       [° C]                                                                         lated   found                               __________________________________________________________________________           77-79 (0.6)          7.3% N 29.8% F                                                                       7.5% N 29.1% F                             C                                                                                    75-76 (0.2)          7.3% N 29.8% F                                                                       7.6% N 29.0% F                             C                                                                                    65 (0.2)##           6.7% N 36.4% F                                                                       6.8% N 36.7% F                             C                                                                                    87-90 (10)           6.7% N 36.4% F                                                                       6.6% N 36.5% F                             C                                                                                    68-70 (0.3)          6.7% N 36.4% F                                                                       7.0% N 35.8% F                             C                                                                                    111  (7)##           6.3% N 34.1% F                                                                       6.5% N 34.5% F                             C                                                                                    66 (0.15)#           5.4% N 44.0% F                                                                       5.6% N 43.5% F                             __________________________________________________________________________

                                      Table IV                                    __________________________________________________________________________         Nitro- and/or                                  Kp/m.p.                   Meth-                                                                              acetamino-                                     (mm)                      od   compound           Reactants                   [° C]              __________________________________________________________________________    C      --                                                                                             CF.sub.3CFCF.sub.2                                    C                                    ##STR69##                                      ##STR70##                                                                    CF.sub.3CFCF.sub.2 74 (0,1)                                                    ##STR72##                                                                    CF.sub.3CFCF.sub.2 89 (0,2)                                              D                                                                                   ##STR74##                                                                     ##STR75##                                                                    48-50R76##                                                                         Aniline                Kp/m.p.  Analysis                            Meth-     and/or                 (mm)     calcu-                              od        hydrochloride          [° C]                                                                           lated     found                     __________________________________________________________________________              73-75 (0.3)             5.4% N 44.0% F                                                                         5.7% N 43.7% F                     C                                                                                       65-67 (0.2)             5.4% N 44.0% F                                                                         5.3% N 43.8% F                     C                                                                                       72-73 (0.3)             5.1% N 41.7% F                                                                         4.9% N 41.3% F                     D                                                                                       62-63R80##              6.8% N 34.5% Cl                                                                       6.5% N  34.3%Cl                     __________________________________________________________________________     (x) Compound described in Ber. 96 (1963) 52;                                  (xx) Compound described in Bull. Soc. Chim. France 5 1957, 581;               (xxx) Compound described in J. Org. Chem. 29 (1964) 5;                   

The novel urea derivatives of the invention are obtained in good yields.They constitute, almost exclusively, crystalline compounds. In mostcases they may be used as they are obtained. Further purification byrecrystallization from the usual organic solvents is also possible.

The novel compounds have a good action against weeds and are superior toknown urea derivatives, for example, the chemically closely relatedN-(3-chloro-4-methoxyphenyl)-N'-methoxy urea (cf. U.S. Pat. No.3,228,762) and metobromuron, in their preserving properties for a numberof important crop plants such as maize, cotton, and legumes.

They are used in the form of wettable powders, emulsion concentrates,dusting powders or granules either alone, or, if desired, in combinationwith other herbicides, soil insecticides or with fertilizers.

Wettable powders are preparations that can be uniformly dispersed inwater and contain, besides an inert substance, a wetting agent, forexample ethoxylated alkylphenols, ethoxylated oleyl- or stearyl-amines,alkyl- or alkylphenylsulfonates and dispersing agents, for example thesodium salt of ligninsulfonic acid,2,2'-dinaphthylmethane-6,6'-disulfonic acid,dibutyl-naphthalene-sulfonic acid or sodium oleylmethylraurine.

Emulsion concentrates are obtained by dissolving the active ingredientin an organic solvent, for example butanol, cyclohexanone,dimethyl-formamide, xylene or aromatic hydrocarbons having a higherboiling point. To prepare good suspensions or emulsions in water wettingagents as specified above are further added.

Dusting powders are obtained by grinding the active ingredients withfinely divided solid substances, for example talc, natural clays,pyrophillite or diatomaceous earth.

Granules can be prepared by atomizing the active ingredient on to anabsorptive, granulated inert material, or by applying to the surface ofgranulated inert materials concentrates of the active ingredient withthe aid of adhesives, for example polyvinyl alcohol, the sodium salt ofpolyacrylic acid or mineral oils. Alternatively, suitable activeingredients may be made into granules, if desired in admixture withfertilizers, in the manner commonly used for the manufacture ofgranulated fertilizers.

The novel compounds of the invention can be used in combination with thefollowing known herbicides enumerated by

    __________________________________________________________________________    urea derivatives                                                                             linuron, chloroxuron, monolinuron,                                            fluometuron, diuron                                            triazine derivatives                                                                         simazin, atrazin, ametryne, prometryne,                                       desmetryne, methoprotryne                                      urazil derivatives                                                                           lenacil, bromacil                                              pyrazone derivatives                                                                         1-phenyl-4-amino-5-chloro-pyridazone (6)                                      (PCA)                                                          growth-promoting                                                                             2,4-dichlorophenoxy-acetic acid (2,4-D)                        preparations   4-chloro-2-methylphenoxy-acetic acid                                          (MCPA), 2,4,5-trichlorophenoxy-acetic                                         acid (2,4,5-T), 4-chloro-2-methyl-                                            phenoxy-butyric acid (MCPB), 2,3,6-                                           trichlorobenzoic acid (TBA)                                    carbamic acid  barban, phenmedipham, triallate,                               derivatives    diallate, vernolate and 2-chloro-                                             allyl-N,N-diethyl-dithiocarbamate (CDEC)                       dinitrophenol derivatives                                                                    dinitro-orthocresol (DNOC), di-                                               nitro-sec.-butylphenol (DNBP),                                                dinoseb acetate                                                chlorinated aliphatic acids                                                                  trichloroacetic acid, dalapon,                                                diphenamide, N,N-diallyl-chloro-                                              acetamide (CDAA)                                               dipyridilium compounds                                                                       paraquat, biquat, morfamquat                                   anilides       N-(3,4-dichlorophenyl)-methacryl-                                             amide (DCMA), propanil, solan,                                                monalide,                                                      nitriles       dichlobenil, ioxynil                                           other preparations                                                                           flurenol                                                       __________________________________________________________________________

When the active ingredients according to the invention are mixed withfertilizers, preparations are obtained which simultaneously have afertilizing and a herbicidal effect.

EXAMPLE 1

Gaseous monomethylamine was introduced into a solution of 0.2 mole (50grams) of 4-(1',1',2'-trifluoro-2'-chloroethoxy)-phenylisocyanate and100 milliliters of petroleum ether at room temperature and whilststirring until the solution was saturated. The reaction mixture wasmaintained for a further hour at 40° C, cooled, and the crystallineproduct was filtered off with suction and recrystallized from a largequantity of benzene.

Yield: 41 grams, melting point 150° - 152° C Analysis: ##STR81##N-[4-(1',1',2'-trifluoro-2'-chloroethoxy)-phenyl]-N'-methyl-ureamolecular weight 282.5

calculated 12.6% Cl 9.9% N found 12.5% Cl 10.1% N

EXAMPLE 2

0.1 mole (12 grams) of methylisocyanate was added at room temperatureand whilst stirring to a solution of 0.2 mole (45 grams) of4-(1',1',2'-trifluoro-2'-chloro-ethoxy)-aniline in 100 milliliters ofabsolute benzene. The reaction mixture was then heated for another 2hours at 40° C. After cooling, the crystalline reaction product wasfiltered off with suction and recrystallized from a small quantity ofn-propanol. Yield 35 grams, melting point 148° - 149° C. The mixedmelting point with the compound prepared according to Example 1 did notshow a depression.

EXAMPLE 3

0.1 mole (5 grams) of O-methylhydroxylamine was added at roomtemperature and with stirring to a solution of 0.1 mole (25 grams) of4-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenylisocyanate in 120milliliters of absolute benzene. The reaction mixture was then heatedfor a further hour at 40° C, cooled, and the crystalline product wasfiltered off with suction and dried.

Yield 24 grams, melting point 111° - 112° C. Analysis: ##STR82##N-[4-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenyl]-N'-methyl-methoxyuresmolecular weight 298.5

calculated 12.0% Cl 9.4% N found 12.3% Cl 9.5% N

EXAMPLE 4

Gaseous dimethylamine was introduced into a solution of 50 grams of4-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenylisocyanate in 100milliliters of petroleum ether at room temperature and whilst stirringuntil solution was saturated. The reaction mixture was then maintainedfor a further hour at 40° C, cooled, the crystalline product wasfiltered off with suction and recrystallized from n-propanol.

Yield 48 grams, melting point 136° - 138° C Analysis: ##STR83##N-[4-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenyl]-N',N'-dimethylureamolecular weight 296.5

calculated 12.0% Cl 9.4 % N found 12.3 % Cl 9.5 % N

EXAMPLE 5

A solution of 0.2 mole (22 grams) of dimethyl-carbamic acid chloride in25 milliliters of absolute benzene was dropped at 40° C with stirringinto a mixture of 0.2 mole (45 grams) of4-(1',1',2'-trifluoro-2'-chloro-ethoxy)-aniline, 200 milliliters ofabsolute benzene and 0.2 mole (20 grams) of triethylamine. The reactionmixture was then heated for a further 2 hours at 40° C. After cooling,the reaction product was filtered off with suction, washed with wateruntil it was free from chlorine and recrystallized twice from n-propanolYield 38 grams, melting point 135° - 138° C. The mixed melting pointwith the compound prepared according to Example 4 did not show adepression.

EXAMPLE 6

0.22 mole (14 grams) of O,N-dimethylhydroxylamine was added at roomtemperature and with stirring to a solution of 0.2 mole (50 grams) of4-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenylisocyanate in 100milliliters of absolute benzene. The reaction mixture was heated for afurther hour at 40° C, cooled, and the crystalline product was filteredoff with suction and recrystallized from i-propanol.

Yield 49 grams, melting point 89° - 90° C. Analysis: ##STR84##N-[4-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenyl]-N-methoxy-N'-methylureamolecular weight 312.5

calculated 9.0% N 11.3% Cl found 8.8% N 11.6% Cl

EXAMPLE 7

A solution of 0.2 mole (58 grams) of4-(1',1',2'-tri-fluoro-2'-chloro-ethoxy)-phenylcarbamic acid chloride in100 milliliters of absolute benzene was dropped at 40° C whilst stirringinto a mixture of 0.2 mole (12 grams) of O,N-di-methylhydroxylamine, 100milliliters of absolute benzene and 0.2 mole (20 grams) oftriethylamine. The reaction mixture was maintained for a further twohours at 40° C. After cooling the reaction product was filtered off withsuction, washed with water until it was free from chlorine andrecrystallized from i-propanol Yield 41 grams, melting point 88° - 89°C. The mixed melting point with the compound prepared according toExample 6 did not show a depression.

EXAMPLE 8

200 milliliters of methanol and 20 milliliters of sodium hydroxidesolution of 33% strength were added to 0.2 mole (60 grams) ofN-[4-(1',1',2'-trifluoro-2'-chloro-ethoxy)phenyl]-N'-methoxyureaprepared according to Example 3. Whilst cooling with ice and stirring,0.22 mole (28 grams) of dimethylsulfate were dropped into the mixture.After stirring for a further hour at 30° - 35° C an excess of water wasadded, the precipitated reaction product was filtered off with suction,washed with water and recrystallized from i-propanol. Yield 45 grams,melting point 87° - 89° C. The mixed melting point with the compoundprepared according to Example 6 did not show a depression.

EXAMPLE 9

0.2 mole (60 grams) ofN-[4-(1',1',2'-trifluoro-2'-chloroethoxy)-phenyl]-N'-methyl-N'-hydroxy-urea,obtained by additive reaction of N-methyl-hydroxylamines with thecorrespondingly substituted phenylisocyanate, were dissolved in 250milliliters of methanol. 0.22 mole NaOH (20 milliliters of sodiumhydroxide solution of 33% strength) and 0.22 mole (28 grams) ofdimethylsulfate were simultaneously added drop by drop whilst stirringat 40° C to the said solution. The mixture was allowed to react for afurther hour at 40° C, an excess of ice water was added, theprecipitated reaction product was filtered off with suction andrecrystallized twice from i-propanol. Yield 38 grams, melting point86° - 88° C. The mixed melting point with the compound preparedaccording to Example 6 did not show a depression.

EXAMPLE 10

300 milliliters of methanol were added to 0.2 mole (57 grams) ofN-[4-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenyl]-N'-hydroxy-urea.While vigorously stirring at a pH of 9 - 10 and a temperature of 20° C,50 milliliters of 10N sodium hydroxide solution and 0.5 mole (63 grams)of dimethyl-sulfate were simultaneously poured into the mixtureobtained. In the second half of the reaction the pH rose to 10 - 11. Thereaction mixture was maintained for another hour at 20° C, then dilutedwith an excess of ice water, the precipitated reaction product wasfiltered off with suction, washed with water and recrystallized twicefrom i-propanol. Yield 40 grams, melting point 86°- 88° C. The mixedmelting point with the compound prepared according to Example 6 did notshow a depression.

The compounds listed in the following table were prepared in a manneranalogous to that of the example indicated in column 3 with the use ofthe reactants indicated in column 4.

       preparations  melting   Example Final product analogous to  point     Analysis No. molecular weight Example reactants ° C calculated     found          11      ##STR85##      1      ##STR86##      CH.sub.3NH.sub.2 90-92  9.9 % N12.6 % Cl 10.1 % N12.6 % Cl      12     ##STR87##      3      ##STR88##      H.sub.2 NOCH.sub.3 82-83  9.4 % N11.9 % Cl  9.6 % N12.0 % Cl  13      ##STR89##      4      ##STR90##      ##STR91##      118-121  9.4 % N12.0 % Cl  9.8 % N12.0 % Cl      14     ##STR92##      10      ##STR93##      H.sub.2 NOH,dimethyl sul-fate/NaOH 79-82  9.0 % N11.3 % Cl  9.1 % N11.2     % Cl      15     ##STR94##      6      ##STR95##      ##STR96##      oil  8.2 % N10.4 % Cl  8.1 % N10.1 % Cl      16     ##STR97##      2      ##STR98##      CH.sub.3NCO 123-125  9.4 % N12.0 % Cl  9.4 % N11.7 % Cl      17     ##STR99##      5      ##STR100##      ##STR101##      126-128  9.0 % N11.4 % Cl  8.8 % N11.2 % Cl      18     ##STR102##      6      ##STR103##      ##STR104##      58-60  8.6 % N10.9 % Cl  8.6 % N11.0 % Cl      19     ##STR105##      4      ##STR106##      ##STR107##      122-123 10.0 % N27.1 % F 10.1 % N27.4 % F      20     ##STR108##     6      ##STR109##      ##STR110##      67-69  9.5 % N25.6 % F  9.5 % N25.2 % F      21     ##STR111##     1      ##STR112##      CH.sub.3NH.sub.2 96-98 10.5 % N28.6 % F 10.6 % N28.5 % F      22     ##STR113##      4      ##STR114##      ##STR115##      113-115 10.0 % N27.1 % F 10.2 % N27.0 % F      23     ##STR116##      10      ##STR117##      H.sub.2 NOHdimethyl sul-fate/NaOH 57-58  9.5 % N25.6 % F  9.7 % N25.7 %     F      24     ##STR118##      1      ##STR119##      ##STR120##      129-131 10.0 % N27.1 % F 10.5 % N 26.7 % F      25     ##STR121##     4      ##STR122##      ##STR123##      124-126  9.5 % N25.8 % F  9.7 % N25.7 % F      26     ##STR124##     8      ##STR125##      dimethylsulfateNaOH 61-63  9.0 % N24.5 % F  9.0 % N23.9 % F  27      ##STR126##      4      ##STR127##      ##STR128##      107-108  8.5 % N34.5 % F  8.7 % N34.2 % F      28     ##STR129##      7      ##STR130##      ##STR131##      50-52  8.1 % N32.9 % F  8.3 % N33.2 % F      29     ##STR132##      4      ##STR133##      ##STR134##      98-99  8.5 % N34.5 % F  8.2 % N34.3 % F      30     ##STR135##      10      ##STR136##      NH.sub.2 OHdimethylsulfateNaOH 48-49  8.1 % N33.0 % F  8.1 % N32.7 % F     31      ##STR137##      7      ##STR138##      ##STR139##      119-120  8.1 % N 33.2 % F  8.3 % N32.6 % F      32     ##STR140##      6      ##STR141##      ##STR142##        7.8 % N31.7 % F  8.1 % N31.1 % F      33     ##STR143##      1      ##STR144##      H.sub.2 NCH.sub.3 99-100 11.3 % N23.0 % F 11.3 % N23.8 % F      34     ##STR145##     4      ##STR146##      ##STR147##      126-128 10.7 % N21.7 % F 10.7 % N21.0 % F      35     ##STR148##      10      ##STR149##      NH.sub.2 OHdimethylsulfateNaOH 41-42 10.1 % N20.5 % F 10.4 % N20.0 % F     36      ##STR150##      4      ##STR151##      ##STR152##      138-140  8.2 % N23.4 % Br  8.2 % N23.0 % Br      37     ##STR153##      6      ##STR154##      ##STR155##      80-82  7.9 % N22.4 % Br  8.0 % N21.9 % Br      38     ##STR156##      1      ##STR157##      CH.sub.3NH.sub.2 89-91  8.6 % N24.4 % F  8.7 % N23.9 % F      39     ##STR158##      4      ##STR159##      ##STR160##      116-117  8.2 % N23.4 % F  8.3 % N23.9 % F      40     ##STR161##      6      ##STR162##      ##STR163##      88-90  7.9 % N22.4 % F  8.0 % N22.4 % F      41     ##STR164##      2      ##STR165##      CH.sub.3NCO 128  8.2 % N  8.4 % N      42     ##STR166##      4      ##STR167##      ##STR168##      123-124  7.9 % N22.5 % Br  8.2 % N22.8 % Br      43     ##STR169##      6      ##STR170##      ##STR171##      58  7.6 % N21.6 % Br  7.7 % N21.8 % Br      44     ##STR172##      5      ##STR173##      ##STR174##      124-126  9.4 % N31.9 % F  9.6 % N31.8 % F      45     ##STR175##      2      ##STR176##      CH.sub.3NCO 154-155 10.2 % N25.8 % Cl 10.3 % N25.6 % Cl      46     ##STR177##      4      ##STR178##      ##STR179##      103-104  9.7 % N24.6 % Cl  9.9 % N24.3 % Cl      47     ##STR180##      6      ##STR181##      ##STR182##      81-82  9.2 % N23.2 % Cl  8.9 % N23.1 % Cl      48     ##STR183##      1      ##STR184##      CH.sub.3NCO 145-146 10.7 % N27.2 % Cl 10.9 % N27.4 % Cl      49     ##STR185##      5      ##STR186##      ##STR187##      153-155 10.2 % N25.8 % Cl 10.1 % N25.8 % Cl      50     ##STR188##      4      ##STR189##      ##STR190##      103-105  8.7 % N33.0 % Cl  9.0 % N32.5 % Cl      51     ##STR191##      6      ##STR192##      ##STR193##      93-94  8.3 % N31.4 % Cl  8.6 % N31.2 % Cl      52     ##STR194##      2      ##STR195##      CH.sub.3NCO 151  9.4 % N  9.4 % N      53     ##STR196##      4      ##STR197##      ##STR198##      144-146  9.0 % N  9.2 % N      54     ##STR199##      3      ##STR200##      H.sub.2 NOCH.sub.3 105  8.9 % N  8.7 % N      55     ##STR201##      6      ##STR202##      ##STR203##      60  8.5 % N  8.4 % N      56     ##STR204##     4      ##STR205##      ##STR206##      103-105  7.6 % N  7.5 % N      57     ##STR207##      2      ##STR208##      CH.sub.3NCO 170-173  9.4 % N  9.7 % N      58     ##STR209##      2      ##STR210##      CH.sub.3NCO 104-106  9.4 % N  9.3 % N      59     ##STR211##      4      ##STR212##      ##STR213##      125  8.9 % N  9.0 % N      60     ##STR214##      3      ##STR215##      H.sub.2 NOCH.sub.3 100-102  8.9 % N  8.7 % N      61     ##STR216##      6      ##STR217##      ##STR218##      74-76  8.5 % N  8.5 % N      62     ##STR219##      1      ##STR220##      H.sub.2 NCH.sub.3 158-159  8.4 % N31.9 % Cl  8.7 % N31.5 % Cl  63      ##STR221##      4      ##STR222##      ##STR223##      200-201  8.1 % N  8.2 % N      64     ##STR224##      6      ##STR225##      ##STR226##      148-150  7.7 % N29.3 % Cl  8.0 % N28.9 % Cl      65     ##STR227##      4      ##STR228##      ##STR229##      155-157  7.5 % N  7.4 % N      66     ##STR230##      2      ##STR231##      CH.sub.3NCO 157-159 10.7 % N27.2 % Cl 11.1 % N26.7 % Cl      67     ##STR232##      4      ##STR233##      ##STR234##      105-106 10.2 % N25.8 % Cl  9.9 % N25.2 % Cl      68     ##STR235##      6      ##STR236##      ##STR237##      72-73  9.6 % N24.4 % Cl  9.6 % N24.0 % Cl      69     ##STR238##      3      ##STR239##      H.sub.2 NOCH.sub.3 118-120 10.1 % N25.6 % Cl  10.5 % N25.1 % Cl  70      ##STR240##      6      ##STR241##      ##STR242##      98-101 9.6 % N24.4 % Cl  9.3 % N24.0 % Cl      71     ##STR243##      4      ##STR244##      ##STR245##      110-112  9.2 % N23.4 % Cl  8.7 % N23.1 % Cl      72     ##STR246##     4      ##STR247##      ##STR248##      65-68  7.8 % N19.7 % Cl  7.4 % N19.9 % Cl      73     ##STR249##     2      ##STR250##      CH.sub.3NCO 156-158  9.1 % N34.4 % Cl  9.2 % N33.9 % Cl      74     ##STR251##      4      ##STR252##      ##STR253##      158-160  7.7 % N43.9 % Br  8.1 % N44.1 % Br      75     ##STR254##      2      ##STR255##      CH.sub.3NCO 182-184  7.2 % N 9.8 % Cl  7.6 % N 9.9 % Cl      76     ##STR256##      2      ##STR257##      CH.sub.3NC O 156-158 10.2 % N25.8 % Cl 10.4 % N25.8 % Cl      77     ##STR258##      4      ##STR259##      ##STR260##      181  9.7 % N24.6 % Cl  9.7 % N24.6 % Cl      78     ##STR261##      6      ##STR262##      ##STR263##      111-113  9.2 % N23.2 % Cl  9.0 % N23.2 % Cl      79     ##STR264##     4      ##STR265##      ##STR266##      171-173  9.2 % N23.2 % Cl  9.4 % N23.4 % Cl      80     ##STR267##      6      ##STR268##      ##STR269##      85-87  8.7 % N22.1 % Cl  8.9 % N22.1 % Cl      81     ##STR270##      2      ##STR271##      CH.sub.3 NCO 182-186  9.5 % N36.0 % Cl  9.3 % N36.0 % Cl      82     ##STR272##      4      ##STR273##      ##STR274##      192-195  9.0 % N34.4 % Cl  9.3 % N 33.8 % Cl      83     ##STR275##      6      ##STR276##      ##STR277##      162-164  8.6 % N32.7 % Cl  8.8 % N32.4 % Cl        4     ##STR278##      1      ##STR279##      H.sub.2 NCH.sub.3 171-173 10.2 % N25.8 % Cl 10.0 % N25.6 % Cl  85      ##STR280##      4      ##STR281##      ##STR282##      192-193  9.7 % N24.6 % Cl  9.9 % N24.6 % Cl      86     ##STR283##      6      ##STR284##      ##STR285##      126-129  9.2 % N23.3 % Cl  9.0 % N23.3 % Cl      87     ##STR286##     2      ##STR287##      CH.sub.3NCO 138  8.9 % N  9.0 % N      88     ##STR288##      3      ##STR289##      H.sub.2 NOCH.sub.3 105-106  8.5 % N  8.8 % N      89     ##STR290##      4      ##STR291##      ##STR292##      114-115  7.9 % N  7.9 % N      90     ##STR293##      2      ##STR294##      CH.sub.3NCO 159-161  8.9 % N  9.2 % N      91     ##STR295##      4      ##STR296##      ##STR297##      95-96  8.6 % N21.7 % Cl  8.7 % N21.3 % Cl      92     ##STR298##      6      ##STR299##      ##STR300##      71  8.2 % N  8.2 % N      93     ##STR301##      4      ##STR302##      ##STR303##      140  8.6 % N21.7 % Cl  8.7 % N21.7 % Cl      94     ##STR304##      6      ##STR305##      ##STR306##      79-  8.2 % N20.7 % Cl  8.2 % N 20.6 % Cl      95     ##STR307##      1      ##STR308##     H.sub.2 NCH.sub.3 162-163  8.9 % N  9.3 % N      96     ##STR309##      5      ##STR310##      ##STR311##      117-119  8.6 % N21.7 % Cl  8.7 % N21.6 % Cl      97     ##STR312##      6      ##STR313##      ##STR314##      89-91  8.2 % N  8.5 % N      98     ##STR315##      1      ##STR316##      H.sub.2 NCH.sub.3 138-140  7.6 % N  7.7 % N      99     ##STR317##      4      ##STR318##      ##STR319##      167-169  7.4 % N  7.1 % N      100     ##STR320##      6      ##STR321##      ##STR322##      60-62  7.1 % N17.9 % Cl  7.3 % N17.6 % Cl      101     ##STR323##      1      ##STR324##      H.sub.2 NCH.sub.3 137-138  8.4 % N32.0 % Cl  8.3 % N31.7 % Cl  102      ##STR325##      3      ##STR326##      H.sub.2 NOCH.sub.3 118  8.0 % N30.4 % Cl  8.1 % N29.9 % Cl  103      ##STR327##      4      ##STR328##      ##STR329##      145  8.1 % N30.6 % Cl  8.2 % N30.2 % Cl      104     ##STR330##      6      ##STR331##      ##STR332##      92-93  7.7 % N29.3 % Cl  8.0 % N29.2 % Cl      105     ##STR333##      N      ##STR334##      H.sub.2 NCH.sub.3 156-158  8.4 % N 32.0 % Cl  8.6 % N31.8 % Cl  106      ##STR335##      4      ##STR336##      ##STR337##      92-94  8.1 % N  8.0 % N      107     ##STR338##      6      ##STR339##      ##STR340##      54-55  7.7 % N  7.9 % N      108     ##STR341##      1      ##STR342##      H.sub.2 NCH.sub.3 137-139  8.4 % N32.0 % Cl  8.6 % N31.6 % Cl  109      ##STR343##      4      ##STR344##      ##STR345##      115-118  8.1 % N  8.2 % N      110     ##STR346##      6      ##STR347##      ##STR348##      96-98  7.7 % N  7.8 % N      111     ##STR349##      4      ##STR350##      ##STR351##      74-76  7.5 % N  7.5 % N      112     ##STR352##      1      ##STR353##      H.sub.2 NCH.sub.3 157-158  7.5 % N21.2 % Br  7.8 % N20.9 % Br  113      ##STR354##      4      ##STR355##      ##STR356##      112  7.2 % N  7.4 % N      114     ##STR357##      6      ##STR358##      ##STR359##      94-97  6.9 % N  7.2 % N      115     ##STR360##      4      ##STR361##      ##STR362##      105-106   6.7 % N  6.7 % n      116     ##STR363##     2      ##STR364##      CH.sub.3NCO 149  8.5 % N  8.6 % N      117     ##STR365##      4      ##STR366##      ##STR367##      159  8.2 % N  8.4 % N      118     ##STR368##      6      ##STR369##      ##STR370##      92-93  7.8 % N  8.0 % n      119     ##STR371##      1      ##STR372##      H.sub.2 NCH.sub.3 168  8.1 % N30.7 % Cl  8.3 % N31.3 % Cl      120     ##STR373##      4      ##STR374##      ##STR375##      145-147  7.8 % N29.6 % Cl  7.6 % N  29.4 % Cl      121     ##STR376##      6      ##STR377##      ##STR378##      105  7.6 % N28.2 % Cl  7.6 % N27.9 % Cl      122     ##STR379##      1      ##STR380##      H.sub.2 NCH.sub.3 136  6.3 % N  6.6 % N      123     ##STR381##      4      ##STR382##      ##STR383##      128-130  6.1 % N  6.2 % N      124     ##STR384##      6      ##STR385##      ##STR386##      69-70  5.9 % N29.7 % Cl  6.0 % N29.3 % Cl      125     ##STR387##      4      ##STR388##      ##STR389##      51-53  5.7 % N  5.7 % N      126     ##STR390##      2      ##STR391##      CH.sub.3NCO 142-144  7.5 % N 9.5 % Cl  7.3 % N 8.9 % Cl      127     ##STR392##      4      ##STR393##      ##STR394##      130-132  7.2 % N 9.2 % Cl  7.3 % N 9.4 % Cl      128     ##STR395##      6      ##STR396##      ##STR397##      78-80  6.9 % N 8.6 % Cl  6.9 % N 8.7 % Cl      129     ##STR398##     2      ##STR399##      CH.sub.3NCO 150-151  8.6 % N  8.5 % N      130     ##STR400##      6      ##STR401##      ##STR402##      94-97  7.9 % N10.0 % Cl  7.9 % N10.0 % Cl      131     ##STR403##      1      ##STR404##      H.sub.2 NCH.sub.3 164-166 12.3 % N 12.1 % N      132     ##STR405##      4      ##STR406##      ##STR407##      104-106 11.5 % N14.6 % Cl 11.8 % N15.2 % Cl      133     ##STR408##      6      ##STR409##      ##STR410##       91-92 10.8 % N 11.1 % N      134     ##STR411##      1      ##STR412##      H.sub.2 NCH.sub.3 121 12.3 % N 12.4 % N      135     ##STR413##     4      ##STR414##      ##STR415##      195 11.5 % N14.6 % Cl 11.4 % N14.4 % Cl      136     ##STR416##      6      ##STR417##      ##STR418##      122 10.8 % N 11.0 % N      137     ##STR419##      1      ##STR420##      H.sub.2 NCH.sub.3 102-105 10.6 % N 10.3 % N      138     ##STR421##      4      ##STR422##      ##STR423##      123-125 10.1 % N25.6 % Cl 10.2 % N25.8 % Cl      139     ##STR424##      3      ##STR425##      H.sub.2 NOCH.sub.3 130-131 10.0 % N 25.4 % Cl 10.1 % N25.3 % Cl  140      ##STR426##      6      ##STR427##      ##STR428##      112-114  9.6 % N  9.6 % N      141     ##STR429##      2      ##STR430##      CH.sub.3NCO 154-155 10.6 % N 10.6 % N      142     ##STR431##      4      ##STR432##      ##STR433##      178-179 10.1 % N25.6 % Cl  9.9 % N25.4 % Cl      143     ##STR434##      8      ##STR435##      H.sub.2 NOCH.sub.3dimethylsulfate 106-108  9.6 % N  9.3 % N  144      ##STR436##      4      ##STR437##      ##STR438##      112-114  9.0 % N11.4 % Cl  9.1 % N11.6 % Cl      145     ##STR439##      10      ##STR440##      NH.sub.2 OHdimethylsulfate 108-109  8.6 % N  8.6 % N      146     ##STR441##      5      ##STR442##      ##STR443##      177-179 10.9 % N13.8 % Cl 10.9 % N14.2 % Cl 147      ##STR444##      6      ##STR445##      ##STR446##      66-68 10.3 % N 10.3 % N      148     ##STR447##      4      ##STR448##      ##STR449##      116-118 10.9 % N13.8 % Cl  10.9 % N14.1 % Cl      149     ##STR450##      10      ##STR451##      NH.sub.2 OHdimethylsulfate 64-66 10.3 % N13.0 % Cl 10.1 % N13.3 % Cl     150      ##STR452##      2      ##STR453##       CH.sub.3NCO 120-122  8.6 % N  8.8 % Cl      151     ##STR454##      4      ##STR455##      ##STR456##      159-162  8.2 % N20.8 % Cl  8.5 % N20.8 % Cl      152     ##STR457##      6      ##STR458##      ##STR459##      58-60   7.9 % N19.9 % Cl  8.1 % N19.5 % Cl      153     ##STR460##      4      ##STR461##      ##STR462##      174-175  7.6 % N19.2 % Cl  7.7 % N18.9 % Cl      154     ##STR463##      6      ##STR464##      ##STR465##      61-63  7.3 % N

EXAMPLE 155

A wettable powder which is easy to disperse in water was obtained bymixing 80 parts by weight ofN-[3-(1',1',2',3',3',3'-hexafluoropropoxy)-phenyl]-N'-, N'-dimethylureaas active ingredient, 17 parts by weight of precipitated silicic acid asinert substance and 3 parts by weight of sodium oleylmethyltaurine aswetting and dispersing agent, and grinding the mixture in a diskattrition mill.

EXAMPLE 156

A dusting powder having good herbicidal properties was obtained bymixing 10 parts by weight of N-[3-methyl-4-(1',1',2',2'-tetrafluoroethoxy)-phenyl]-N'-methyl-N'-methoxyurea as activeingredient and 90 parts by weight of talc as inert substance andcomminuting the mixture in a cross beater mill.

EXAMPLE 157

An emulsion concentrate was obtained from 15 parts by weight ofN-[3-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenyl]-N',N'-dimethylurea,75 parts by weight of cyclohexanone as solvent and 10 parts ofnonyl-phenol.sup.. 10 AeO as emulsifier.

The following comparative examples serve to illustrate the invention butthey are not intended to limit it thereto.

COMPARATIVE EXAMPLE 1

    ______________________________________                                        In a greenouse the following weeds                                            wild mustard     Sinapis arvensis                                             chickweed        Stellaria media                                              field camomile   Anthemis arvensis                                            barnyard grass   Echinochloa crus-galli                                       annual meadow grass                                                                            Poa annua                                                    and maize and cotton (Gossypium sp.) were sown.                               ______________________________________                                    

The surface of the soil was srayed with the following compounds of theinvention in the form of wettable powders suspended in water:

I n-[3-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenyl]-N-methyl-urea (cf.Example 11)

Iin-[3-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenyl]-N'-methyl-N'-methoxy-urea(cf. Example 14)

Iii n-[3-(1',1',2'-trifluoro-2'-chloro-ethoxy)-phenyl]-N',N'-dimethylurea (cf. Example 13).

As comparative substance the known urea herbicideN-(3-chloro-4-methoxyphenyl)-N'-methyl-N'-methoxy-urea IV (cf. U.S. Pat.No. 3,228,762) was used.

The evaluation after 6 weeks with concentrations of 0.6 and 1.2kilograms of active ingredient per hectare gave the followig result:

    ______________________________________                                        Degree of Damage in percent                                                   ______________________________________                                               I       II        III       IV                                                0.6  1.2    0.6    1.2  0.6  1.2  0.6 1.2                              ______________________________________                                        weeds                                                                         (average                                                                      of 5 types)                                                                            75     90     93   99   98   100  76  86                             maize    0      0      0    0    10   20   30  50                             cotton   0      0      0    0     0    0   60  100                            ______________________________________                                    

The herbicidal effect of substance I of the invention was approximatelyequal to tht of the known comparative compound IV, whereas substances IIand III were distinctly superior. Moreover, the novel compounds didalmost no harm to the cultivated plants maize and cotton, which werestrongly injured and partly destroyed by the comparative compound IV.

With regard to the herbicidal effect and the damage to the specifiedcultivated plants the following compounds

a. had an effect similar to that of compound I above

N-[3-methyl-4-(1',1',2',2'-tetrafluoro-ethoxy)-phenyl]-N'-methylurea(cf. Example 24)

N-[3-(1',1',2'-trifluoro-2'-bromo-ethoxy)-phenyl]-N',N'-dimethylurea(cf. Example 39)

N-[3-(1',1',2'-trifluoro-2'-bromo-ethoxy)-phenyl]-N'-methylurea (cf.Example 38)

N-[3-(1',1',2'-trifluoro-2'-bromo-ethoxy)-phenyl]-N'-methyl-N'-methoxyurea(cf. Example 40)

N-[4-(1',1',2',2'-tetrafluoro-ethoxy)-phenyl]-N',N'-dimethylurea (cf.Example 19)

N-[3-(1',1',2'-trifluoro-ethoxy)-phenyl]-N'-methylurea (cf. Example 33)

b. had an effect similar to that of compound II above

N-[3-(1',1',2',2'-tetrafluoro-ethoxy)-phenyl]-N'-methyl-urea (cf.Example 21)

N-[3-methyl-4-(1',1',2',2'-tetrafluoro-ethoxy)-phenyl]-N'-methyl-N'-methoxyurea(cf. Example 26)

N-[3-(1',1',2',3',3',3'-hexafluoro-propoxy)-phenyl]-N',N'-dimethylurea(cf. Example 29)

N-[3-(1',1',2'-trifluoro-ethoxy)-phenyl]-N'-methyl-N'-methoxyurea (cf.Example 35)

c. had an effect similar to that of compound III above

N-[3-(1',1',2',2'-tetrafluoro-ethoxy)-phenyl]-N'-methyl-N'-methoxyurea(cf. Example 23)

N-[3-methyl-4-(1',1',2',2'-tetrafluoro-ethoxy)-phenyl]-N' -N'-dimethylurea (cf. Example 25)

N-[3-(1',1',2'-trifluoro-ethoxy)-phenyl]-N',N'-dimethylurea (cf. Example34)

COMPARATIVE EXAMPLE 2

At the same time as the test described above, a comparative test wascarried out with horse beans, soybeans (Glycine soya), kidney beans(Phaseolus vulgaris) and maize and the aforesaid weeds, in which testcompoundsn-[3-(1',1',2',3',3',3'-hexafluoro-propoxy)-phenyl]-N'-methyl-N'-methoxyurea(cf. Example 30) and

Vin-[4-(1',1',2',3',3',3'-hexafluoro-propoxy)-phenyl]-N',N'-dimethylurea(cf. Example 28)

were compared with comparative compound

Iv n-(3-chloro-4-methoxyphenyl)-N'-methyl-N'-methoxyurea.

The evaluation after 6 weeks gave the following result (concentrations0.6 and 1.2 kilograms of active ingredient per hectare).

    ______________________________________                                        Degree of damage in percent                                                           V         VI          IV                                                      0.6   1.1     0.6     1.2   0.6   1.2                                 ______________________________________                                        weeds (average                                                                of 5 types)                                                                             90      93      82    88    76    86                                maize     0       0       0     0     30    50                                soybean   0       0       0     0     40    95                                horse bean                                                                              0       10      0     0     30    65                                kidney bean                                                                             0       10      0     0     20    50                                ______________________________________                                    

With an approximately equal or slightly superior herbicidal effect thenovel compounds V and VI did no harm to the 4 types of cultivatedplants, which were strongly damaged by comparative compound IV.

COMPARATIVE EXAMPLE 3

In a further test compound VIIN-[3-(1',1',2',2'-tetrafluoro-ethoxy)-phenyl]-N',N'-dimethylurea (cf.Example 22)

was sprayed in the form of an aqueous suspension on the surface of asoil into which the weeds wild mustard, field camomile, barnyard grass,annual meadow grass and pigweed (Amaranthus retroflexus) had been sowntogether with cotton.

As comparative compound the known urea product metobromuron VIIIN-(4-bromophenyl)-N'-methyl-N'-methoxyurea, was used. The result isindicated in the following table. The compounds were used inconcentrations of 0.3, 0.6 and 1.2 kilograms per hectare.

    ______________________________________                                        Degree of damage in percent                                                           VII           VIII                                                            0.3   0.6     1.2     0.3   0.6   1.2                                 ______________________________________                                        weeds (average                                                                of 5 types                                                                              96      98      100   75    87    94                                cotton    0       0       0     35    40    75                                ______________________________________                                    

Compound VII of the invention had a distinctly better herbicidal effectthan comparative compound VIII and did no harm at all to the cottonwhich was considerably damaged by metobromuron.

COMPARATIVE EXAMPLE 4

Seeds of cotton (Gossypium sp.) and various weeds were sown in pots. Onthe same day wettable powder formulae suspended in water of thepreparations

I = n-3-(1',1',2'-trifluoroethoxy)-phenyl-N',N'-dimethylurea (cf.Example 34)

Ii = n-3-(1',1',2'-trifluoroethoxy)-phenyl-N'-methyl-N'-methoxyurea (cf.Example 35)

Iii = n-3-(1',1',2'-trifluoroethoxy)-phenyl-N'-methylurea (cf. Example33)

were sprayed onto the surface of the soil. As comparative substance thepreparation of fluometuron(N-3-trifluoro-methylphenyl-N',N'-dimethylurea) was used.

An evaluation 5 weeks after the treatment revealed that cotton was notdamaged in any place with amounts of 0.3 and 0.6 kilogram of activeingredient per hectare. With respect to the weeds Sinapis arvensis,Amaranthus retroflexus, Kochia scoparia and Chenopodium album, theeffect of the substances in accordance with the invention was about asgood as the effect of the comparative substances, i.e. the weedsmentioned above were completely killed everywhere with 0.3 and 0.6kilogram per hectare. With respect to some other weeds, however,differences were to be seen, which is shown in the following survey.

    ______________________________________                                        Effect on the weeds, expressed as "degree of damage in %"                                      Effect with                                                  Species of plant                                                                          Preparation                                                                              0.3        0.6 kg/ha                                   ______________________________________                                        Ipomoea purpurea                                                                          I          100        100                                                     II         100        100                                                     III        100        100                                                     fluometuron                                                                              85         85                                          Datura stramonium                                                                         I          75         100                                                     II         70         100                                                     III        80         95                                                      fluometuron                                                                              30         60                                          Eleusine indica                                                                           I          100        100                                                     II         95         100                                                     III        95         100                                                     fluometuron                                                                              60         85                                          Setaria viridis                                                                           I          100        100                                                     II         95         100                                                     III        80         100                                                     fluometuron                                                                              65         85                                          ______________________________________                                    

These values show that the preparations in accordance with the inventionhave a far better effect on the species of weeds mentioned above thanthe comparative substance.

COMPARATIVE EXAMPLE 5

In a greenhouse wild mustard and oat were sown in pots. On the day ofsowing the soil was treated with a 25 % suspension in water of wettablepowders of N-[4-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N'-methylurea andN-[4-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N',N' -dimethylurea,respectively.

As comparative substance the known urea herbicideN-(4-chlorophenyl)-N'-methyl-N'-isobutinylurea was used.

The test results are indicated in Table I. In the table are given theamount of active ingredient in kilograms per hectare and the effect ofthe preparation in "degrees of damage"; 100 means total destructionwhereas 0 indicates that the plant was not at all damaged. The figuresdefined the damage in percent.

An evaluation 6 weeks after the treatment exhibited that inconcentrations that are destructive to wild mustard the novel compoundsdo oat very little harm only. With a 100% destruction of the wildmustard the oat was damaged to a degree of 10% only. The correspondingvalue of the comparative substance amounted to a 75% destruction of theoats. With a degree of damage of the weed of 70 - 80%, which is fullysatisfactory in practice, the oat was still damaged to about 50% by thecomparative substance, whereas the novel compounds were fully safe. Onthe other hand the application of double the amount of the herbicidalagent, which is possible in practice at any time, for example withoverlapping spray zones on the field, did not noticeably increase thedamage of the oats whereas with the comparative substance the damagerose at once to 90%. Hence, it follows that the application of the novelpreparations is much safer.

                                      TABLE 1                                     __________________________________________________________________________    Preparation                 Damage with kilograms of active ingredient                                    per hectare                                       containing           Test plant                                                                           10 kg/ha                                                                             5 kg/ha                                                                              2.5 kg/ha                                                                            1.2 kg/ha                                                                            0.6                   __________________________________________________________________________                                                            kg/ha                 N-[4-(1',1'-difluoro-2',2'-                                                   dichloro-ethoxy)-phenyl]-N'-                                                                       wild                                                     methylurea           mustard                                                                              100 %  100 %  100 %  95 %   75 %                  N-[ 4-(1',1'-difluoro-2',2'-                                                  dichloro-ethoxy)-phenyl]-N',N'-                                                                    "      100 %  100 %  100 %  90 %   70 %                  dimethylurea                                                                  N-(4-chlorophenyl)-N'-methyl-                                                                      "      100 %  100 %  100 %  100 %  80 %                  N"-isobutinylurea                                                             N-[4-(1',1'-difluoro-2',2'-                                                   dichloro-ethoxy)-phenyl]-N'-                                                  methylurea           oat     10 %   0 %    0 %    0 %    0 %                  N-[4-(1',1'-difluoro-2',2'-                                                   dichloro-ethoxy)-phenyl]-N',N'-                                               dimethylurea         "       20 %   10 %   0 %    0 %    0 %                  N-(4-chlorophenyl)-N'-methyl-N'-                                              isobutinylurea       "      100 %  100 %   90 %  75 %   50                    __________________________________________________________________________                                                            %                 

COMPARATIVE EXAMPLE 6

Cotton, wild mustard and wild oat were sown in pots in a greenhouse and3 weeks after germination the pots were treated with an aqueoussuspension of N-[4-(1',2'-dichlorovinyloxy)-phenyl]-N'-methylurea(preparation I) and a corresponding suspension ofN-[4-(1',2'-dichlorovinyloxy)-phenyl]-N',N'-dimethylurea (preparationII), respectively. The respective wettable powders used for thepreparation of the aqueous suspensions contained 25% of activeingredient and 75% of known additives.

As comparative substance N-(3-trifluoromethylphenyl)-N',N'-dimethylurea(preparation III) known as herbicide for cotton cultivations was used.

The results of the comparative test are indicated in Table 2. Theresults were evaluated 4 weeks after the treatment.

Preparations I and II containing the active ingredients according to theinvention had a better effect on wild mustard than comparative substanceIII. With wild oat the effect of preparation II was almost equal to thatof comparative preparation III, while the effect of preparation I wassomewhat weaker. However, preparations I and II did less damage to thecotton. In a concentration of 1.2 kilograms/ha which destroys the wildmustard preparation III caused a brightening of the cotton leaves whilehigher concentrations partially involved slight necrosis. Incontradistinction thereto, the herbicides according to the inventioncaused scarcely perceptible damages to the leaves (10% damage) only in 2to 4 times higher concentrations.

The above results reveal that when cotton is treated after germinationthis crop plant is less damaged by the herbicides according to theinvention with an about equal effect on the weeds.

                                      TABLE 2                                     __________________________________________________________________________                  Damage with kilograms of active ingredient per hectare          Preparation                                                                          Test plant                                                                           5 kg/ha                                                                              2.5 kg/ha                                                                            1.2 kg/ha                                                                            0.6 kg/ha                                  __________________________________________________________________________    I      Wild mustard                                                                         100 %  100 %  100 %  90 %                                       II            100 %  100 %  100 %  100 %                                      III           100 %  100 %  100 %  60 %                                       I      Wild oats                                                                            75 %   45 %   30 %   30 %                                       II            95 %   75 %   75 %   50 %                                       III           95 %   80 %   75 %   50 %                                       I      Cotton 10 %   10 %    0 %    0 %                                       II            10 %    0 %    0 %    0 %                                       III           50 %   40 %   30 %   10 %                                       __________________________________________________________________________     Preparation I = N-[4-(1',2'-dichlorovinyloxy)-phenyl]-N'-methylurea           Preparation II 32  N-[4-(1',2'-dichlorovinyloxy)-phenyl]-N'-dimethylurea      Preparation III = N-(3-trifluoromethyl-phenyl)-N',N'-dimethylurea        

COMPARATIVE EXAMPLE 7

In a greenhouse wild mustard, carrots, peas and kidney beans were sownin pots. On the day of sowing the soil was treated with an aqueoussuspension of a wettable powder containing as active ingredientN-[4-(3',3'-dichloroallyloxy)-phenyl]-N'-methoxyurea (preparation IV)and N[4-(3',3'-dichloroallyloxy)-phenyl]-N',N' -dimethylurea(preparation V), respectively. As comparative substance a chemicallyresembling urea derivative was used (cf. U.S. Pat. No. 2,655,447), i.e.N-(4-allyloxyphenyl)-N',N' -dimethylurea (preparation VI). Allpreparations contained 25% of active ingredient and 75% of usualadditives in the form of a wettable powder.

The results were evaluated 5 weeks after the treatment. Particulars areindicated in Table 3.

Although all preparations used had about the same herbicidal effect onwild mustard, preparations IV and V according to the invention did mustless damage to the three crop plants than comparative preparation VI.The difference was particularly evident with the effect of preparationIV on carrots. In a concentration of 1.2 kilograms/ha which killed thewild mustard the carrots did not suffer any damage while they weresubstantially destroyed with the same concentration of comparativepreparation VI.

Preparation IV substantially saved the kidney beans in the indicatedconcentration and even with 4 times the concentration the degree ofdamage was only 30%. As compared herewith preparation VI when applied ina concentration of 1.2 kilograms/ha caused a slight to distinct damageof 20 to 40% whereas too high a concentration, which can never beavoided in practice, injured the plants to an extent of up to 90% with 5kilograms per hectare.

It should be stressed that preparation V was particularly safe for peaswhereas the action of preparation IV was a little less favorable. Thecomparative substance distinctly damaged the peas so that the practicaluse thereof is unsuitable. In this case, too, it can be seen that thenovel herbicides are even tolerated in two to four times the usualconcentration.

The above results reveal that with approximately the same herbicidaleffect as the comparative substance, the herbicides according to theinvention substantially save peas, carrots and kidney beans so that theyare excellently suitable for the control of weeds in such crop plants.

                                      TABLE 3                                     __________________________________________________________________________                  Damage with kg/ha of active ingredient                          Test plant                                                                           Preparation                                                                          5 kg/ha                                                                              2.5 kg/ha                                                                            1.2 kg/ha                                                                            0.6 kg/ha                                                                            0.3 kg/ha                                                                            0.15 kg/ha                   __________________________________________________________________________    Wild mustard                                                                          IV    100 %  100 %  100 %  95 %   75 %   30 %                                 V     100 %  100 %  100 %  85 %   45 %   20 %                                 VI    100 %  100 %  100 %  90 %   70 %   50 %                         Carrot  IV    40 %   20 %    0 %    0 %    0 %    0 %                                 V     65 %   50 %   50 %   20 %   10 %   10 %                                 VI    100 %  100 %  100 %  80 %   70 %   50 %                         Pea     IV    30 %   30 %   20 %   10 %    0 %    0 %                                 V     20 %   20 %    0 %    0 %    0 %    0 %                                 VI    90 %   80 %   50 %   30 %   20 %   20 %                         Kidney bean                                                                           IV    30 %   20 %    0 %    0 %    0 %    0 %                                 V     50 %   30 %   20 %   20 %    0 %    0 %                                 VI    90 %   75 %   40 %   20 %   20 %   10 %                         __________________________________________________________________________     Preparation IV =                                                              N-[4-(3',3'-dichloroallyloxy)-phenyl]-N'-methyl-N'-methoxyurea                Preparation V = N-[4-(3',3'-dichloroallyloxy)-phenyl]-N',N'-dimethylurea      Preparation VI = N-(4-allyloxyphenyl)-N',N'-dimethylurea?                

COMPARATIVE EXAMPLE 8

    ______________________________________                                        The dicotyledonous weeds                                                               wild mustard   Sinapis arvensis                                               chickweed      Stellaria media                                                field camomile Anthemis arvensis                                     and      annual blackgrass                                                                            Alopecurus myosuroides                                and the                                                                       crop plants                                                                            pea            Pisum sativum                                                  horse bean     Vicia faba                                                     spring wheat   Triticum aestivum                                              spring rye     Secale cereale                                                 spring barley  Hordeum distichum                                     and      cotton         Gossypium sp.                                         ______________________________________                                    

were sown in big plastics boxes filled with humous sandy loam and theboxes were covered. On the day of sowing the surface of the soil wastreated with an aqueous suspension of a wettable powder containing asactive ingredient

N-[3-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N',N'-dimethylurea(preparation VII) or

N-[3-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N'-methoxy-N'-methylurea(preparation VIII), respectively. As comparative substances various ureacompounds and a triazine derivative were used, chosen according to thecrop plants, namely:

N-3,4-dichlorophenyl-N'-methyl-N'-methoxyurea (linuron) (preparation IX)and

2-chloro-4,6-bis-ethylamino-s-triazine (simazin) (preparation X)

for pea, horse bean and the cereals,

N-4-chlorophenyl-N'-methyl-N'-isobutinylurea (buturon) (preparation XI)

for the cereals,

N-3-trifluoromethylphenyl-N',N'-dimethylurea (fluometuron) (preparationXII)

and

N-3,4-dichlorophenyl-N',N'-dimethylurea (diuron) (preparation XIII) forcotton.

The boxes were placed in a hotbed and the results were evaluated 5 weeksafter the treatment.

Table 4 shows that preparations VII and VIII according to the inventionhave, on the average, approximately the same effect on weeds as theindicated comparative substances, particularly on the dicotyledonousweeds. But also the foxtail grass still suffers a distinct damage. Thedestructive concentration for most of the weeds is about 0.6 kilogram ofactive ingredient per hectare for all preparations, i.e. the novelherbicides as well as the comparative substances.

                                      Table 4                                     __________________________________________________________________________    Amount applied                                                                              Damage with kg/ha of active ingredient                          Preparation                                                                           Test plant                                                                          0.15 kg/ha                                                                           0.6 kg/ha                                                                            2.5 kg/ha                                                                            Test plant                                                                            0.15 kg/ha                                                                          0.6 kg/ha                                                                            2.5                   __________________________________________________________________________                                                            kg/ha                 VII     Wild  70%    100%   100 %  Chickweed                                                                            90%    100 %  100%                  VIII    mustard                                                                             60 %   100 %  100%          70%    100%   100%                  IX            90%    100%   100%          100 %  100%   100%                  X             80 %   100 %  100 %         90 %   100 %  100 %                 XI            50 %    70 %  100 %         70 %   100 %  100 %                 XII           60 %   100 %  100 %         90 %   100 %  100 %                 XIII          50 %    80 %  100 %         80 %   100 %  100 %                 VII     Field 60 %   100 %  100 %  Foxtail grass                                                                        30 %    60 %   90 %                 VIII    camomile                                                                            50 %    90 %  100 %         10 %    40 %   60 %                 IX            80 %   100 %  100 %         30 %    60 %   80 %                 X             60 %   100 %  100 %         50 %    80 %  100 %                 XI            70 %   100 %  100 %         60 %    80 %  100 %                 XII           80 %   100 %  100 %         10 %    40 %   60 %                 XIII          80 %   100 %  100 %         30 %    60 %   80                   __________________________________________________________________________                                                            %                 

Table 5 shows, however, that the novel herbicides are distinctly saferfor some crop plants than the comparative substances. Pea, horse bean aswell as cotton were not damaged or damaged to a very small extent onlyby 0.6 kilogram per hectare of the preparations according to theinvention, whereas the same amount of the corresponding comparativesubstances injured the specified plants to a lesser or greater extent.The selectivity was especially pronounced when surplus amounts wereapplied as it is relatively often the case in practice. With 4 times thenormal concentration, that is to say 2.5 kilograms per hectare, thehorse bean exhibited some damage whereas cotton and pea remainedpractically undamaged. The comparative substances caused much moreserious damages, above all preparations IX and X on the pea. Even 16times the concentration (10 kg/ha) of the novel compounds hardly damagedcotton and pea, whereas the same concentrations of the comparativesubstances strongly injured the cotton and completely destroyed the pea.

Moreover, under practical conditions preparation VIII had a much betterselectivity in cultivations of various cereals (wheat, rye, barley) thanthe comparative substances.

                                      Table 5                                     __________________________________________________________________________             Test plant: pea  Test plant: horse bean                                                                         Test plant: cotton                 Amount applied                                                                         0.15                                                                              0.6 2.5 10.0 0.15                                                                              0.6 2.5 10.0 0.15 0.6  2.5  10.0                preparation                                                                            kg/ha                                                                             kg/ha                                                                             kg/ha                                                                             kg/ha                                                                              kg/ha                                                                             kg/ha                                                                             kg/ha                                                                             kg/ha                                                                              kg/ha                                                                              kg/ha                                                                              kg/ha                                                                              kg/ha               __________________________________________________________________________    VII      0%   0% 10%  30 %                                                                              0 % 20 %                                                                              50 %                                                                               90 %                                                                              0 %   0 %  0 % 10 %                VIII     0 %  0 %                                                                              10 %                                                                               30 %                                                                              0 %  0 %                                                                              20 %                                                                              50 % 0 %   0 % 10 % 20 %                IX       0 % 20 %                                                                              60 %                                                                              100 %                                                                              0 % 40 %                                                                              70 %                                                                              100 %                                   X        0 % 30 %                                                                              60 %                                                                              100 %                                                                              0 % 20 %                                                                              60 %                                                                              100 %                                   XII                                        0 %  10 % 30 % 50 %                XIII                                       0 %  10 % 30 % 60                  __________________________________________________________________________                                                              %                            Test plant: wheat                                                                              Test plant: rye  Test plant: barley                          0.15                                                                              0.6 2.5 10.0 0.15                                                                              0.6 2.5 10.0 0.15 0.6  2.5  10.0                         kg/ha                                                                             kg/ha                                                                             kg/ha                                                                             kg/ha                                                                              kg/ha                                                                             kg/ha                                                                             kg/ha                                                                             kg/ha                                                                              kg/ha                                                                              kg/ha                                                                              kg/ha                                                                              kg/ha               __________________________________________________________________________    VIII      0 %                                                                               0 %                                                                              20 %                                                                               40 %                                                                              0 %  0 %                                                                              30 %                                                                               60 %                                                                              0 %   0 % 20 % 30 %                IX        0 %                                                                              30 %                                                                              70 %                                                                              100 %                                                                              10 %                                                                              50 %                                                                              90 %                                                                              100 %                                                                              0 %  10 % 30 % 70 %                X        20 %                                                                              70 %                                                                              90 %                                                                              100 %                                                                              0 % 50 %                                                                              80 %                                                                              100 %                                                                              30 % 70 % 100                                                                                100 %               XI       10 %                                                                              50 %                                                                              70 %                                                                              100 %                                                                              0 % 40 %                                                                              90 %                                                                              100 %                                                                              0 %  30 % 70 % 100                 __________________________________________________________________________                                                              %               

COMPARATIVE EXAMPLE 9

In the same manner as in Comparative Example 8 the substances

N-[3-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N'-methoxyurea(preparation XIV) and

N-[3-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N'-methylurea(preparation XV) were tested as to their effect on wild mustard,chickweed, pea, spring wheat and spring barley and additionally on

    ______________________________________                                        oat                Avena sativa                                               sorghum millet     Sorghum millet                                             maize              Zea mays                                                   kidney bean        Phaseolus vulgaris                                         ______________________________________                                    

Table 6 shows that the novel herbicides XIV and XV exhibited a goodeffect on dicotyledonous weeds such as wild mustard and chickweed, anddid not injure a series of crop plants. Even when applied in double theconcentration they caused at most a minor damage, if any.

                                      Table 6                                     __________________________________________________________________________    Damage with kilograms active ingredient per hectare                           Amount applied                                                                         Test plant: wild mustard                                                                        Test plant: chickweed                                                                           Test plant: pea                  preparation                                                                            1.2 kg/ha                                                                           2.5 kg/ha                                                                           5 kg/ha                                                                             1.2 kg/ha                                                                           2.5 kg/ha                                                                           5 kg/ha                                                                             1.2 kg/ha                                                                           2.5 kg/ha                                                                           5                    __________________________________________________________________________                                                             kg/ha                XIV      70 %  100 % 100 % 70%   100 % 100 % 0 %   0 %   20 %                 XV       90 %  100 % 100 % 100 % 100 % 100 % 0 %   0 %   20 %                          Test plant: oat   Test plant: barley                                                                              Test plant: wheat                         1.2 kg/ha                                                                           2.5 kg/ha                                                                           5 kg/ha                                                                             1.2 kg/ha                                                                           2.5 kg/ha                                                                           5 kg/ha                                                                             1.2 kg/ha                                                                           2.5 kg/ha                                                                           5                    __________________________________________________________________________                                                             kg/ha                XIV      0 %   0 %   20 %  0 %   0 %   10 %  0 %   0 %   10 %                 XV       0 %   0 %   30 %  0 %   0 %    0 %  0 %   0 %    0 %                          Test plant: sorghum millet                                                                      Test plant: maize Test plant: bean                          1.2 kg/ha                                                                           2.5 kg/ha                                                                           5 kg/ha                                                                             1.2 kg/ha                                                                           2.5 kg/ha                                                                           5 kg/ha                                                                             1.2 kg/ha                                                                           2.5 kg/ha                                                                           5                    __________________________________________________________________________                                                             kg/ha                XIV      0 %   0 %    0 %  0 %   0 %   10 %  0 %   20 %  40 %                 XV       0 %   0 %    0 %  0 %   0 %    0 %  0 %   0 %   20                   __________________________________________________________________________                                                             %                

COMPARATIVE EXAMPLE 10

In a field test on loamy soil peas and horse beans were treated on theday of sowing with an aqueous suspension of

N-[4-(2'-chloroethoxy)-phenyl]-N',N'-dimethylurea (XVI)

N-[4-(2'-chloroethoxy)-phenyl]-N'-methyl-N'-methoxyurea (XVII)

N-[4-(2'-chloroethoxy)-phenyl]-N'-methylurea (XVIII), respectively. Eachplot had a size of 20 square meters. Each suspension was applied to 4plots. The comparative substance was a urea preparation on the basis ofN-[4-(p-chlorophenoxy)-phenyl]-N',N'-dimethylurea (chloroxuron, XIX)often used for various vegetable cultivations.

The data of the evaluation 8 weeks later by visual inspection arecalculated to give the degree of damage in percent.

As weeds the following dicotyledonous types were present:

    ______________________________________                                        chickweed         Stellaria media                                             shepherd's purse  Capsella bursa-pastoris                                     dead nettle       Lamium amplexicaule                                         groundsel         Senecio vulgaris                                            wild mustard      Sinapis arvensis and                                        knotweed          Polygonum aviculare                                         ______________________________________                                    

The results of the evaluation of these types are indicated. Asmonocotyledonous weed

annual blackgrass Alopecurus myosuroides

was present.

Table 7 shows that the action on dicotyledonous weeds of two of thesubstances according to the invention, namely XVI and XVII, was slightlysuperior to that of comparison substance XIX, while the action of thethird compound XVIII was approximately equal to that of the latter. Thenovel herbicides had, however, a distinctly better effect on the oftencumbersome annual blackgrass. Moreover, the results indicate that allthree novel preparations were less harmful to the pea, whereas at leasttwo of the three compounds, namely XVI and XVIII were distinctly saferfor the horse bean than the comparative substance.

The advantage of the compounds according to the invention is thereforebased on the fact that they are safer for peas and horse beans thanknown herbicides and, moreover, that they control more effectively weedygrasses such as annual blackgrass.

                                      Table 7                                     __________________________________________________________________________    Amount applied   Degree of damage with kilogram of active ingredient per                       hectare                                                      preparation                                                                           Test plant                                                                             1.25 kg/ha                                                                           2.5 kg/ha                                                                           5.0 kg/ha                                                                           Test plant                                                                          1.25 kg/ha                                                                           2.5 kg/ha                                                                            5.0                   __________________________________________________________________________                                                            kg/ha                 XVI     Dicotylous                                                                             90 %   98 %  100 % Pea   0 %    10 %   20 %                  XVII    weed     90 %   98 %  100 %       0 %     0 %   10 %                  XVIII            60 %   73 %   95 %       0 %     0 %   10 %                  XIX              65 %   85 %   98 %       20 %   30 %   40 %                  XVI     Annual blackgrass                                                                      60 %   80 %   90 % Horse 0 %    10 %   10 %                  XVII             60 %   70 %   80 % bean  0 %    10 %   30 %                  XVIII            40 %   50 %   60 %       0 %     0 %    0 %                  XIX               0 %   20 %   30 %       0 %    20 %   30                    __________________________________________________________________________                                                            %                 

COMPARATIVE EXAMPLE 11

In a hotbed the following compounds

N-[3-chloro-4-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N'-methylurea(preparation I)

N-[3-chloro-4-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N',N'-dimethylurea(preparation II) and

N-[3-chloro-4-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N'-methyl-N'-methoxyurea(III)

were tested as to their herbicidal effect and safety in a series of cropplants. The seeds of the following weeds

    ______________________________________                                        wild mustard      Sinapis arvensis                                            chickweed         Stellaria media                                             field camomile    Anthemis arvensis                                           groundsel         Senecio vulgaris                                            ______________________________________                                    

and the following crop plants

    ______________________________________                                        pea               Pisum sativum                                               horse bean        Vicia faba                                                  kidney bean       Phaseolus vulgaris                                          carrot            Daucus carota                                               spring rye        Secale cereale                                              spring barley     Hordeum distichum                                           spring wheat      Triticum aestivum                                           oat               Avena sativa                                                maize             Zea mays                                                    rice              Oryza sativa and                                            cotton            Gossypium sp.                                               ______________________________________                                    

were sown in boxes filled with humous sandy loam. The surface of thesoil was sprayed on the same day with aqueous suspensions of thespecified preparations. After 5 weeks the plants were classified byvisual inspection and the values obtained were calculated to give thedegree of damage in percent. As comparative substances the followingcompounds were used:

for cotton: N-3,4-dichlorophenyl-N',N'-dimethylurea (diuron, IV)

for the vegetables: N-4-(p-chlorophenoxy)-phenyl-N',N'-dimethylurea(chloroxuron, V)

for the cereals: N-4-chlorophenyl-N'-methyl-N'-methoxyurea (monolinuron,VI)

Table 8 shows that the compounds according to the invention I, II andIII have approximately the same effect on the germinating dicotyledonousweeds as the known comparative substances. The concentration sufficientfor a normal control of the weeds is, in general, in the range of from0.6 to 1.2 kilograms of active ingredient per hectare.

Table 9 indicates, however, that the novel herbicides are safer for thecrop plants. Compounds I and II are safer for cotton, pea, horse beanand kidney bean, compound II is safer for the carrot and all three novelcompounds are safer for the cereals than the comparative substances.Even when applied in a surplus concentration the novel compounds onlyinvolve little damage.

Hence, it follows that the compounds according to the invention aredistinctly safer, above all for cotton and kidney beans, furthermore forrye, oat, maize and a series of other crop plants than the correspondingcomparative substances.

                                      Table 8                                     __________________________________________________________________________    Amount applied  Degree of damage with kilograms of active ingredient per                      hectare                                                       preparation                                                                           Test plant                                                                            0.6 kg/ha                                                                            1.2 kg/ha                                                                            5.0 kg/ha                                                                            Test plant                                                                          0.6 kg/ha                                                                            1.2 kg/ha                                                                            5.0                  __________________________________________________________________________                                                             kg/ha                I       Wild mustard                                                                          50 %   60 %    95 %  Chick weed                                                                          70 %    85 %  100 %                II              80 %   95 %   100 %        100 %  100 %  100 %                III             80 %   90 %    90 %        90 %    90 %  100 %                IV              80 %   100 %  100 %        100 %  100 %  100 %                V               60 %   80 %    90 %        70 %    80 %  100 %                VI              75 %   90 %   100 %        90 %   100 %  100 %                I       Field camomile                                                                        70 %   85 %    95 %  Groundsel                                                                           80 %    90 %  100 %                II              80 %   95 %   100 %        90 %   100 %  100 %                III             60 %   70 %   100 %        80 %    90 %   95 %                IV              90 %   100 %  100 %        100 %  100 %  100 %                V               75 %   85 %   100 %        70 %    80 %   95 %                VI              80 %   95 %   100 %        90 %   100 %  100                  __________________________________________________________________________                                                             %                

                                      Table 9                                     __________________________________________________________________________    Amount applied                                                                              Action on cultivated plants                                     preparation                                                                           Test plant                                                                          0.6 kg/ha                                                                           1.2 kg/ha                                                                           5.0 kg/ha                                                                           Preparation                                                                          Test plant                                                                          0.6 kg/ha                                                                          1.2 kg/ha                                                                            5.0                  __________________________________________________________________________                                                             kg/ha                I       Cotton                                                                               0 %   0 %   0 %   I     Carrots                                                                              0 % 10 %   40 %                 II             0 %   0 %   0 %  II            0 %  0 %   10 %                 IV            10 %  30 %  40 %   V            0 % 20 %   40                   __________________________________________________________________________                                                             %                            Test plant: pea   Test plant: horse bean                                                                           Test plant: kidney bean          Preparation                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                           5.0 kg/ha                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                            5.0 kg/ha                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                         5.0                    __________________________________________________________________________                                                           kg/ha                  I        0. %  0 %  10 %   0 %   0 %   10 %   0 %   0 %                                                                               0 %                   II       0 %   0 %  20 %   0 %   0 %   30 %   0 %   0 %                                                                               0 %                   V       10 %  30 %  40 %  20 %  20 %   40 %   0 %  20 %                                                                              55                     __________________________________________________________________________                                                           %                              Test plant: rye   Test plant: barley Test plant: wheat                Preparation                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                           5.0 kg/ha                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                            5.0 kg/ha                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                           5.0                  __________________________________________________________________________                                                             kg/ha                I        0 %   0 %   0 %   0 %   0 %   20 %   0 %   0 %   0 %                 II       0 %   0 %  30 %   0 %  20 %   25 %   0 %   0 %  10 %                  III     0 %   0 %  30 %   0 %  30 %   40 %   0 %   0 %  20 %                 VI      30 %  80 %  100 % 30 %  60 %   90 %  40 %  70 %  100                  __________________________________________________________________________                                                             %                            Test plant: oat   Test plant: maize  Test plant: rice                 Preparation                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                           5.0 kg/ha                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                            5.0 kg/ha                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                           5.0                  __________________________________________________________________________                                                             kg/ha                I        0 %   0 %  10 %   0 %   0 %    0 %   0 %   0 %  10 %                 II       0 %   0 %  10 %   0 %   0 %   10 %   0 %  10 %  20 %                  III     0 %   0 %   0 %   0 %  `0 %    0 %   0 %  10 %  30 %                 VI      30 %  60 %  100 % 20 %  30 %   50 %  30 %  50 %  90                   __________________________________________________________________________                                                             %                

COMPARATIVE EXAMPLE 12

N-[3-methyl-4-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N'-methyl-N'-methoxyurea(VII),

N-[3-methyl-4-(1',1'-difluoro-2',2'-dichloroethoxy)-phenyl]-N',N'-dimethylurea(VIII),

N-4-chlorophenyl-N'-methyl-N'-methoxyurea (monolinuron, IX)

N-4-chlorophenyl-N'-methyl-N'-isobutinylurea (buturon, X) mixed productof 5% of 2-chloro-3,6-bisethylamino-s-triazin (simazin) and 22.5% of2-methylmercapto-4-isopropylamino-6-(3'-methoxy)-propylamino-s-triazine(XI)

were tested as follows:

    ______________________________________                                        wild mustard      Sinapis arvensis                                            chickweed         Stellaria media                                             field camomile    Anthemis arvensis                                           fat hen           Chenopodium album                                           and the crop plants                                                           spring wheat      Triticum aestivum                                           spring barley     Hordeum distichum                                           oats              Avena sativa                                                rice              Oryza sativa                                                sugar beet        Beta vulgaris and                                           horse bean        Vicia faba                                                  ______________________________________                                    

were sown in boxes filled with humous sandy loam. On the same day thesurface of the soil was sprayed with an aqueous suspension ofpreparations VII and VIII. As comparative substances two urea compoundsoften used for cereals (XI and X) and a mixed triazine product alsosuitable for cereals were used. Comparative product IX is also suitablefor horse beans.

After the treatment the boxes were placed in a hotbed and kept thereinfor 6 weeks until the test was evaluated. Table 10 shows that the novelcompounds VII and VIII had about the same action on weeds as thecomparative substances. With an amount applied of 1.2 kilograms perhectare of active ingredient the latter killed all weeds whereas thesame amount of the novel compounds strongly damaged the weeds and ahigher amount fully destroyed the weeds.

                  Table 10                                                        ______________________________________                                        Degree of damage on weeds with                                                Preparation                                                                            0.6 kg/ha   1.2 kg/ha   2.5 kg/ha                                    ______________________________________                                        VII      54 %        73 %        100 %                                        VIII     76 %        89 %        100 %                                        IX       92 %        99 %        100 %                                        X        92 %        100 %       100 %                                        XI       90 %        100 %       100 %                                        ______________________________________                                    

The indicated values are average values for all four types of weeds.

The following Table 11 reveals, however, that with an amount of 1.2kg/ha the comparative substances strongly or very strongly injured thecereals mentioned, whereas the novel compounds saved completely oralmost completely wheat, barley, oat and rice in an amount of 1.2 and2.5 kg/ha. Furthermore, the horse bean was not or only slightly damagedby the novel compounds, whereas comparative substance IX stronglydamaged this type of plant. Novel substance VII saved the sugar beetwhen applied in the indicated amount, whereas all comparative substancesdestroyed the beet almost completely.

The novel compounds have the advantage that in an amount sufficient todestroy or strongly injure a series of important field weeds they savenumerous crop plants such as wheat, barley, oat, rice and horse bean,partially also sugar beet, whereas comparative substances often used forthe indicated cultivations exhibit a much stronger damaging action.

                                      Table 11                                    __________________________________________________________________________    Action on crop plants                                                                  Test plant: wheat Test plant: barley                                                                              Test plant: oat                  Preparation                                                                            0.6 kg/ha                                                                           1.2 kg/ha                                                                           2.5 kg/ha                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                           2.5 kg/ha                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                           2.5                  __________________________________________________________________________                                                             kg/ha                VII       0 %   0 %   0 %   0 %   0 %   0 %   0 %   0 %   0 %                 VIII     10 %  10 %  20 %   0 %   0 %   30 %  0 %   0 %  10 %                 IX       20 %  50 %  95 %  20 %  40 %   50 % 40 %  80 %  100 %                X        65 %  80 %  90 %  55 %  95 %  100 % 60 %  90 %  100 %                XI       85 %  90 %  100 % 70 %  90 %  100 % 80 %  85 %  100                  __________________________________________________________________________                                                             %                             Test plant: rice  Test plant: sugar beet                                                                          Test plant: horse bean           Preparation                                                                            0.6 kg/ha                                                                           1.2 kg/ha                                                                           2.5 kg/ha                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                           2.5 kg/ha                                                                           0.6 kg/ha                                                                           1.2 kg/ha                                                                           2.5                  __________________________________________________________________________                                                             kg/ha                VII       0 %   0 %   0 %   0 %   0 %   20 %  0 %   0 %   0 %                 VIII      0 %   0 %   0 %  100 % 100 % 100 %  0 %  10 %  20 %                 IX       80 %  95 %  100 % 95 %  100 % 100 % 50 %  60 %  80 %                 X        40 %  55 %  70 %  100 % 100 % 100 %                                  XI       70 %  80 %  90 %  100 % 100 % 100 %                                  __________________________________________________________________________

COMPARATIVE EXAMPLE 13

    ______________________________________                                        In a greenhouse the following weeds                                           wild mustard     Sinapis arvensis                                             chickweed        Stellaria media                                              field camomile   Anthemis arvensis                                            barnyard grass   Echinochloa crus-galli                                       annual meadow grass                                                                            Poa annua                                                    and the crop plants                                                           maize            Zea mays                                                     wheat            Triticum sativum                                             horse bean       Vicia faba                                                   pea              Pisum sativum                                                carrot           Daucus carota                                                ______________________________________                                    

were sown in boxes filled with humous sandy loam. On the same day thesurface of the soil was sprayed with wettable powders suspended in waterof the following compounds of the invention

I. n-[3-chloro-4-(2'-chloroethoxy)-phenyl]-N',N'-dimethyl-urea (cf.Example 138) and

Ii. n-[3-trifluoromethyl-4-(2'-chloroethoxy)-phenyl]-N',N'-dimethyl-urea(cf. Example 144)

As comparative substance the known urea derivative fluometuron =N-3-trifluoromethylphenyl-N',N'-dimethyl-urea was used.

The evaluation after 6 weeks with concentrations of 0.3 and 0.6 kilogramof active ingredient per hectare gave the following results:

    ______________________________________                                        Degree of damage in percent                                                   (100 = complete destruction - 0 = no damage)                                                               comparative                                             I         II          substance                                               0.3   0.6     0.3     0.6   0.3   0.6                                  ______________________________________                                        weeds                                                                         (average of                                                                   5 types) 90      100     92    99    92    99                                 maize    0       0       0     0     20    60                                 wheat    0       0       0     0     40    70                                 horse bean                                                                             0       o       0     0     60    90                                 pea      0       0       0     0     25    70                                 carrot   0       10      0     0     30    50                                 ______________________________________                                    

The novel compounds and the comparative substance showed an excellentherbicidal effect. The novel compounds did no harm to the crop plantsmaize, wheat, horse bean, pea and carrot, which plants were strongly orvery strongly injured by the comparative substance.

COMPARATIVE EXAMPLE 14

In a further test and in the same manner as described in comparativeExample 1, the five types of weeds and as crop plants maize and cotton(Gossypium sp.) were sown. The surface of the soil was sprayed with awettable powder suspended in water and containing as active ingredient

Iii. n-[3-chloro-4-(2'-chloroethoxy)-phenyl]-N'-methyl-N'-methoxy-urea(cf. Example 140).

As comparative substance the chemically closely related urea herbicide

N-(3-chloro-4-methoxyphenyl)-N'-methyl-N'-methoxy-urea was used.

The evaluation after 6 weeks with concentrations of 0.6 and 1.2kilograms of active ingredient per hectare gave the following result:

    ______________________________________                                        Degree of damage in percent                                                              III       comparative substance                                               0.6   1.2     0.6       1.2                                        ______________________________________                                        weeds (average of                                                             5 types)     80      96      76      86                                       maize        0        0      30      50                                       cotton       0       10      60      100                                      ______________________________________                                    

The herbicidal effect of compound III was approximately equal to that ofthe comparative substance but the novel compound did no harm to the cropplants maize and cotton which were strongly damaged and partly evendestroyed by the comparative substance.

COMPARATIVE EXAMPLE 15

In boxes filled with humous sandy loam, spring wheat (Triticum aestivum)and spring barley (Hordeum distichum) were sown together with the weedswild oat (Avena fatua) and various broad-leaved types (Sinapis arvensis,Stellaria media, Galium aparine, Anthemis arvensis, Veronica arvensisand Polygonum persicaria). On the same day the surface of the soil wassprayed with aqueous suspensions of the compounds of the invention

Iv. n-[3-methyl-4-(2'-chloroethoxy)-phenyl]-N',N'-dimethylurea (cf.Example 148) and

V. n-[3-methyl-4-(2'-chloroethoxy)-phenyl]-N'-methyl-N'-methoxyurea (cf.Example 149) As comparative compound the triazine derivatives known asherbicide for cereals

2-methylmercapto-4-ethylamino-6-tert.butyl-amino-s-triazine was used.

The evaluation after 5 weeks with concentrations of 0.6 kilogram ofactive ingredient per hectare gave the following result:

    ______________________________________                                        Degree of damage in percent                                                   (100 = complete destruction 0 = no damage)                                    type of plant                                                                              IV      V       comparative substance                            ______________________________________                                        wheat        10       0       0                                               barley        0       0       0                                               weeds                                                                         wild oat     100     100     20                                               other weeds                                                                   (average value)                                                                            94      86      92                                               ______________________________________                                    

The table shows that all preparations had a good or very good actionagainst broad-leaved weeds and did no harm to cereals. But the verycumbersome wild oat which is difficult to combat was not damaged by theknown herbicide for cereals whereas the compounds of the inventiondestroyed the wild oat without doing any harm to the botanically closelyrelated cereals wheat and barley.

What we claim is:
 1. A herbicidal preparation containing an effectiveamount of ##STR466## as the active ingredient, in combination with aninert solid or liquid carrier, a solvent, adhesive, wetting agent,dispersing agent or grinding auxiliary.
 2. A preparation as claimed inclaim 1 in the form of a wettable powder.
 3. A preparation as claimed inclaim 1 in the form of a solution or emulsion concentrate.
 4. The methodof selectively controlling weeds in cotton which comprises applying aherbicidal preparation as in claim 1 to the locus thereof in aconcentration which strongly damages said weeds and saves the cotton.